Science Buddies: "Ask an Expert"

I'm currently doing a project on the effect the pH of a dissolution medium has on the dissolution rate of Paracetamol/Acetaminophen. I hope to recreate the USP apparatus 2 (Paddle) for my procedure, but I am unsure of how to. May I know the main components of the paddle set-up, and if its possible for me to re-create one in the school lab? I would also like to seek clarification if this is the best way to test my project. I hope for a reply soon, as the experiment is due on 28/05/13. Thanks!

PHYSICS APPARATUS IN MY SCHOOL
1 ACCUMULATOR, 2V
2 AIR POT
3 ALUMINIUM ANGLE BAR
4 ALUMINIUM WEIGHING PAN
5 AMMETER, 0-1A
6 AMMETER, 3A
7 ANGULAR MOMENTUM
8 BALANCE
9 BALL AND RING APPARATUS
10 BALL-BRASS
11 BANANA PLUG
12 BATTERY CHARGER
13 BATTERY HOLDER
14 BATTERY TESTER
15 BELL
16 BINOCULAR
17 BLACK AND SILVER CONTAINER
18 BOILER with TAP
19 BOYLE'S LAW APPARATUS
20 BREAD BOARD
21 BULB HOLDER
22 BULBS
23 CATHODE RAY TUBE
24 CELLULOSE ACETATE STRIPS
25 CENTRIFUGAL TOY
26 COLOUR LAMP
27 COMBUSTION TUBES
28 COMPASS
29 CONDUCTIVITY APPARATUS
30 CONVEX LENS
31 CORKBOARD
32 CROCODILE CLIPS
33 DATALOGGER SYSTEM
34 DEFY GRAVITY
35 DENSITY SET
36 DETACHABLE CELL HOLDER
37 DISPLACEMENT CAN
38 DRYFIT CHARGING CABLES
39 DRY CELL
40 DYNAMO
41 EBONITE ROD
42 EDDY CURRENT
43 ELECTRIC BELL
44 ELECTRODES PLATINIUM
45 ELECTRONIC WEIGHING SCALE (DIGITAL)
46 ELECTROSCOPE
47 FAN
48 FISH TANK
49 FRIDGE
50 GALVANOMETER
51 GAS LIGHTER
52 GENERATOR
53 GLASS BLOCK
54 GLASS MARBLE
55 GRATING CARD
56 HAIR DRYER
57 HALF- METER RULER
58 HEAT ABSORPTION COMPARATOR
59 HEAT CONDUCTIVITY APPARATUS
60 HOFFMAN'S ELECTROLYSIS APPT.
61 HOT PLATE, STAINLESS
62 HYDROMETER
63 ILLUSION BANK
64 INDUCED CURRENT APPT / INDUCTION COIL APPT
65 INGENHOUSE APPARATUS
66 JOCKEY
67 KETTLE
68 KINETIC THEORY MODEL
69 LASER POINTER
70 LASER REFRACTION TANK
71 LENS
72 LENS HOLDER
73 LENZ'S LAW APPT
74 LIGHT BULB IN SERIES / PARALLEL
75 LUBRICANT OIL
76 MAGNETS
77 MEASURING CYLINDER
78 METER RULER
79 MICROMETER
80 MICROPHONE
81 MICROPHONE SANHA HEAD
82 MICROWAVE OWEN
83 MIRASCOPE
84 MIRROR
85 MODEL OF EYE
86 MOP BUCKET AND WRINGER
87 MOTOR
88 MULTIMETER
89 NEON LAMP
90 NEWTON COLOUR DISC
91 NOVA 5000 DATALOGGER
92 OPTICAL LIGHT BOX SET WITH COLOUR MIXING
93 OPTICAL PIN
94 OPTICAL SET
95 OPTICS TESS
96 OSCILLOSCOPE
97 PAPER CUTTER
98 PENDULUM BOB
99 PIN HOLE CAMAERA
100 PING PONG BALL
101 PLASTIC BOX
102 PLASTIC TRAY
103 PLASTICINE
104 PLIERS
105 PLOARIZE EYE PIECE
106 POLARIZATION EXPT.SET
107 POLY ROLLING TOY
108 POLYTHENE STRIPS
109 POTENTIOMETER
110 POWER SUPPLY 0-12V
111 PRESSURE SYRINGE
114 PULLEYS
115 PUMP
116 PVC PIPING
117 RAY BOX
118 RAY BOX (IEC)
119 RAY BOX (WOODEN)
120 RAY BOX LAMP
121 RESISTANCE COIL
122 RHEOSTAT
123 RING BEARING
124 RIPPLE TANK
131 SENSOR
134 SLOTTED WEIGHT
135 SMOKE CELL APPARATUS
136 SOLAR OVEN SET
137 SOLDERING FLUX
138 SOLDERING IRON
139 SOLDERING LEAD
140 SOLENOID KIT
141 SOUND LEVEL METER
142 SPEAKERS
143 SPIRIT LEVEL
144 SPRING
145 SPRING BALANCE
146 STANLEY CRIMPING TOOL
147 STEEL CUTTER
148 STOPWATCH
149 STROBOSCOPE
150 SUBMARINE SET
151 SUNDIAL
152 SWITCHES
153 THERMISTER
154 THERMOMETER
155 THERMOSTAT STAINLESS STEEL
156 THOMSON COIL
158 TICKER TAPE TIMER
159 TICKER TAPE TIMER PAPER ROLL
160 TRANSFORMER DC 0-12V
161 TRAY BASKET
164 ULTRA VIOLET LAMP
165 VACUUM FLASKS
166 VACUUM PUMP
167 VAN DE GRAAF GENERATOR
169 VENTILATION APPARATUS
171 VIBRATOR WITH DIPPERS
172 VOLT METER
173 VOLT METER
174 VOLT METER 0-6V
175 WASHING MACHINE
176 WAVE MOTION MACHINE
177 WHEEL
178 WHIMSHURT MACHINE APPARATUS
179 WHITE SCREEN
181 WIRE
182 WIRE STRIPPER

Welcome to the Forum.

I know next to nothing about testing pharmaceuticals; however I did find a relevant article in Wikipedia:

http://en.wikipedia.org/wiki/Dissolution_testing

Reference 18 in this article links to a PDF document that discusses the details of fluid flow in the USP II Apparatus. Figure 1 of this article is a drawing, with dimensions, of the specified Apparatus.

Reading the article, it became clear to me that the exact geometry of the container and paddle matter a great deal in the performance of the Apparatus, so if you wish to replicate it you would need to make an accurate replica of the device -- creating a somewhat similar set up from odds and ends in your physics lab will not do. (The whole paper is intended, in fact, to demonstrate that the use of the USP II Apparatus should not be allowed in testing drugs because the results depend too sensitively on the precise way tests with the Apparatus are performed.)

If you would tell us your motivations for wanting to perform dissolution testing, we might be able to come up with some suggestions for appropriate science fair topics. It might be even more useful for you to use our topic selection "wizard" to find some science fair projects that you might find interesting; start at the URL

https://www.sciencebuddies.org/science- ... gister.php

Best of luck!